Comparison of calculated data for the flammability and the oxidation potential according to ISO 10156 with experimentally determined values

The classification of flammable gas mixtures is based on either testing or calculation methods proposed by the revised international standard ISO 10156. This standard is used for classification of physical hazards in Chapters 2.2 and 2.4 of the UN Globally Harmonized System of Classification and Labelling of Chemicals (GHS) and in the UN Recommendations on Transport of Dangerous Goods (TDG). The test methods of flammability and oxidizing potential in this standard were developed by BAM. Earlier versions of this standard are not based on triangular diagrams and on the reference combustible substance “ethane”. The old material characteristics, especially in case of oxidizing potential, are based mostly on practical experience without any quantifiable test results. First time it is possible to compare experimental results from the CHEMSAFE database with the newly developed calculation method. In this paper the basic principles of the calculation methods are presented and the methods are validated by examples. A comparison of experimental flammability data with classification results gained by the calculation methods of ISO 10156 is demonstrated.     

基于成组生物毒性测试的PM2.5毒性

为了准确评估PM_(2.5)的综合生物毒性,采用发光细菌急性毒性、斑马鱼胚胎急性毒性和体外人肺腺癌细胞(A549)毒性试验对常州市冬季雾-霾天、冬季正常天和夏季这3个时间段的PM_(2.5)进行生物毒性评价,并结合大气理化指标进行分析.结果表明,3个时间段的PM_(2.5)均表现出急性毒性或发育毒性.冬季雾-霾天、冬季正常天和夏季PM_(2.5)对发光细菌的毒性单位(toxicity unit,TU)值分别为1. 74(有毒)、1. 19(有毒)和0. 92(微毒);对斑马鱼胚胎的TU值从大到小排列为:冬季正常天(TU=1. 14,有毒)、冬季雾-霾天(TU=0. 79,微毒)和夏季(TU=0,无毒);对A549的TU值为:冬季雾-霾天(TU=0. 61,微毒)夏季(TU=0. 38,微毒)冬季正常天(TU=0. 31,微毒).在发育毒性方面,除夏季PM_(2.5)样品,其余2个时间段的PM_(2.5)均对斑马鱼胚胎发育有影响,主要表现出心包囊肿、脊椎弯曲和尾部畸形.平均毒性(average toxicity,Av Tx)、毒性指数(toxic print,Tx Pr)和最敏感测试(most sensitive test,MST)综合毒性评价方法表明冬季雾-霾天和冬季正常天PM_(2.5)均表现出有毒,夏季则表现出微毒,以冬季雾-霾天PM_(2.5)样品的综合毒性最高.此外,3种测试生物对PM_(2.5)污染物的敏感度排序为发光细菌斑马鱼胚胎 A549.理化指标和生物毒性的相关性分析结果表明,PM_(2.5)中所含的污染物对生物毒性效应产生影响,可为PM_(2.5)生物毒性综合评价和人体健康风险评估提供依据.     

石灰/粉煤灰水合反应制备高活性脱硫剂机理分析

以粉煤灰的特殊结构为基础 ,分析了石灰 粉煤灰水合反应制备高活性脱硫剂的反应产物、反应过程 ,以及添加剂和压力水合的机制     

Oxidation of diesel soot on binary oxide CuCr(Co)-based monoliths

Binary oxide systems (CuCr₂O₄, CuCo₂O₄), deposited onto cordierite monoliths of honeycomb structure with a second support (finely dispersed Al₂O₃), were prepared as filters for catalytic combustion of diesel soot using internal combustion engine's gas exhausts (O₂, NO_x, H₂O, CO₂) and O₃ as oxidizing agents. It is shown that the second support increases soot capacity of aforementioned filters, and causes dispersion of the particles of spinel phases as active components enhancing thereby catalyst activity and selectivity of soot combustion to CO₂. Oxidants used can be arranged with reference to decreasing their activity in a following series: O₃ ? NO₂ > H₂O > NO > O₂ > CO₂. Ozone proved to be the most efficient oxidizing agent: the diesel soot combustion by O₃ occurs intensively (in the presence of copper chromite based catalyst) even at closing to ambient temperatures. Results obtained give a basis for the conclusion that using a catalytic coating on soot filters in the form of aforementioned binary oxide systems and ozone as the initiator of the oxidation processes is a promising approach in solving the problem of comprehensive purification of automotive exhaust gases at relatively low temperatures, known as the “cold start” problem.     

Oxidation of diesel soot on binary oxide CuCr(Co)-based monoliths

Binary oxide systems(Cu Cr2O4, Cu Co2O4), deposited onto cordierite monoliths of honeycomb structure with a second support(finely dispersed Al2O3), were prepared as filters for catalytic combustion of diesel soot using internal combustion engine’s gas exhausts(O2, NOx, H2 O, CO2) and O3 as oxidizing agents. It is shown that the second support increases soot capacity of aforementioned filters, and causes dispersion of the particles of spinel phases as active components enhancing thereby catalyst activity and selectivity of soot combustion to CO2. Oxidants used can be arranged with reference to decreasing their activity in a following series: O3 NO2> H2 O > NO > O2> CO2. Ozone proved to be the most efficient oxidizing agent: the diesel soot combustion by O3 occurs intensively(in the presence of copper chromite based catalyst) even at closing to ambient temperatures.Results obtained give a basis for the conclusion that using a catalytic coating on soot filters in the form of aforementioned binary oxide systems and ozone as the initiator of the oxidation processes is a promising approach in solving the problem of comprehensive purification of automotive exhaust gases at relatively low temperatures, known as the "cold start" problem.     

Advances in research on haloalkane dehalogenases and its sulfur mustard degradation function北大核心CSCD

Sulfur Mustard (bis-(2-chloroethyl) sulphide, HD), also known as yperite, is one of the most important blister agents. It could react with a large number of biological molecules with a strong cytotoxicity effect, resulting in blistering, erosion and necrosis of the skin and various tissues. Recently, several classes of microbial enzymes have been found to be able to degrade HD with high catalytic activity but no disadvantages of the common chemical decontamination of HD. Haloalkane dehalogenases (HLDs, EC3.8.1.5) draws great research attention for environmentally friendly decontaminating HD with only nontoxic thiodiglycol produced. In order to provide theoretical reference basis for enzymatic decontamination of HD, this paper reviews the observation and evolutionary relationship, structures, substrate specificities, catalytic properties and potential applications of these HLDs with high catalytic hydrolysis of HD. The analysis shows that these HLDs belonging to the same subfamily have different substrate specificities but similar spatial structures of the catalytic triad contributing to the common SN2 nucleophilic substitution reaction mechanism for catalytic hydrolysis of HD. The paper also suggests that the problems on improving poor stability of HLDs and efficiency of catalytic hydrolysis of HD should be addressed by methods of molecular biology, genetic engineering and immobilized techniques.     

Metals removal from aqueous solution by iron-based bonding agents

GOAL AND SCOPE AND BACKGROUND: The application of a promising method, termed sorptive flotation, for the removal of chromium(VI) and zinc ions was the aim of the present paper. A special case of sorptive flotation is adsorbing colloid flotation. Suitable sorbent preparation techniques have been developed in the laboratory. METHODS: Sorptive flotation, consisting of the sorption and flotation processes combined in series, has proved to give fast and satisfactory treatment of the industrial streams and effluents bearing dilute aqueous solutions of zinc and chromium(VI). RESULTS AND DISCUSSION: Goethite has proved to be effective for the removal of chromium(VI) and zinc ions. Also, adsorbing colloid flotation with ferric hydroxide (as the co-precipitant) could be an alternative method to the above-mentioned separation of metal ions. In both cases, chromium(VI) (pH=4) and zinc (pH=7) removal was about 100%. CONCLUSION: The reasons for selecting the iron-based bonding materials, like goethite and/or in-situ produced ferric hydroxide, are that they are cheap, easily synthesized, suitable both for cation and anion sorption, and, furthermore, that they present low risks for adding a further pollutant to the system. Promising results were obtained. RECOMMENDATION AND OUTLOOK: The application of goethite and in-situ produced ferric hydroxide has demonstrated their effectiveness in the removal of heavy metal ions, such as chromium anions and zinc cations. A proposed continuation of current work is the utilization of similar iron oxides, for instance synthesized akaganeite. The comparison between the results reported in this paper with the results reported in the literature, also deserves attention.     

Manganese-catalyzed degradation of phosphonic acids

The non-biodegradable and chemically very stable phosphonates are used in a variety of industrial applications including cooling waters, oil production and textile industry. We show here that they are degraded in the presence of Mn(II) and oxygen. The half-life for the reaction is 9 min near neutral pH. The presence of other cations such as Ca(II) and Zn(II) considerably slows down the reaction by competition with Mn(II) for the phosphonate. The reaction involves the oxidation of complexed Mn(II) by oxygen to Mn(III) and the subsequent oxidation of phosphonate by Mn(III) thus yielding two stable phosphonic acid breakdown products. The oxidation also proceeds in the presence of the mineral manganite (Mn(III)OOH), and yields the same breakdown products. The use of a newly developed chromatographic method revealed the presence of the breakdown products in wastewater. The results show that manganese-catalyzed oxidation might be an important pathway for phosphonate degradation in natural waters. Electronic Publication     

砂页岩赤红壤磷肥活化效果及其机理研究

应用不同活化剂处理不同性质的磷肥，并对其在砂页岩赤红壤中的生物效应及作用机理进行了研究。结果表明，在砂页岩赤红壤上，施用供试的儿种经活化剂处理的磷肥均能显著提高蔬菜生物量。砂页岩赤红壤中的铁、锰质量分数与磷素的有效性有密切的关系，且在还原条件下，土壤铁、锰对磷的固定作用更大；硅、钙可促进土壤中磷的释放。供试活化剂不仅可促进难溶磷的释放，还可控制水溶性磷的释放，使土壤供磷性能平稳；有机活化剂的用量，用于难溶性磷促释时其质量分数为3％，用于水溶性磷控释时其质量分数约为14％。在土壤-植物体系中，活化剂对磷的促释和控释机理是它通过对土壤铁、锰、铝质量分数的调节而实现对磷的活化。     

Simulation of aquatic food web and species interactions by adaptive agents embodied with evolutionary computation: a conceptual framework

Individual-based and state variable-based adaptive agents (AA) are discussed regarding their relevance to different types of ecosystems. Individual-based AA proved applicable to a spatially explicit simulation of highly simplified terrestrial food webs. State variable-based AA with evolutionary computation (EC) embodied are suggested for the simulation of aquatic food webs and plankton species interactions. Embodiment of EC in AA can be achieved by evolving predictive rules (ER), differential equations (EDE) or artificial neural networks (ANN) derived from a diverse lake database. In order to provide ecosystem simulation with resilience to environmental change, agent banks can be created containing alternative agents for same species or functional groups from different lakes. State variable-based AA are currently tested for aquatic ecosytem simulation by means of a diverse lake database. It promises to overcome constraints by the rigidity of traditional lake ecosystem models.